Ventricular extrasystoles on ECG

Clinical significance and organic causes

Virtually any organic myocardial lesion, as well as disruptions in cardiac regulation, can be accompanied by the appearance of extrasystoles. Ventricular excitability disturbances require close attention: to assess the prognosis, the clinician must accurately determine the frequency of pathological episodes and their duration.

In clinical practice, extrasystole often acts as a concomitant manifestation of severe cardiac and iatrogenic pathologies:

• Hypertrophic cardiomyopathy: accompanied by frequent premature contractions and paroxysmal tachycardia, which entails a high risk of sudden cardiac death.
• Alcoholic cardiomyopathy: accumulation of specific arrhythmogenic substances and the development of myocardial stromal lipomatosis provoke paroxysms that can progress to ventricular fibrillation.
• Inflammatory processes: in latent myocarditis, ECG changes in the form of extrasystole are sometimes the only objective marker of ongoing carditis.
• Arrhythmogenic right ventricular cardiomyopathy and mitral valve prolapse are also common organic substrates.
• Toxic and drug-related factors: cardiac glycoside overdose leads to a pathological increase in ventricular automaticity, while rapid intravenous administration of vinca alkaloids causes tachycardia and slowed intraventricular conduction.

Topical ECG diagnostics

Determining the specific source of the ectopic impulse in the ventricles is based on analyzing the QRS complex morphology. In ventricular extrasystole, this complex widens and deforms, beginning to visually resemble a bundle branch block pattern. It is important to understand that this is not a true conduction block, but a specific reflection of how excitation propagates from an abnormal focus.

Functional extrasystole and pediatric aspects

Premature contractions do not always indicate myocardial damage. Functional rhythm disorders are very common, especially in childhood and adolescence (up to 45% of all arrhythmia cases in children). Manifestation can occur even in the neonatal period, but a sharp peak in detection occurs during puberty, which is associated with major autonomic and hormonal changes in the body.

Criteria for a benign (functional) nature of arrhythmia:

1. Peak detection in the prepubertal and pubertal periods.
2. Marked rhythm irregularity.
3. Positive exercise response: the number of pathological complexes decreases sharply or they disappear completely during physical activity and transition to the orthostatic position.
4. Topically, such extrasystoles most often originate from the right ventricle or have a supraventricular origin.

To rule out organic myocardial damage and structural abnormalities, patients with suspected arrhythmia are invariably scheduled for echocardiography (EchoCG) and chest radiography.

Advanced monitoring and diagnostic workup

Standard resting ECG is the baseline method for detecting asymptomatic pathologies, but its diagnostic window is time-limited. If a patient complains of episodic palpitations, presyncope, syncope, or dizziness, 24-hour Holter ECG monitoring (Holter ECG) is indicated.

Holter monitoring has a much higher sensitivity, capturing transient abnormalities. Its most important task is to determine the circadian dependence of the arrhythmia (correlation with sleep and wakefulness phases), which directly dictates the choice of therapeutic tactics. Diagnostic rule: if the patient experienced syncope or a palpitation attack while wearing the monitor, but the device did not record a rhythm disturbance, the cardiac cause of the symptoms is ruled out.

Since excitability disturbances are often extracardiac in origin, diagnosis requires a multidisciplinary approach:

• Provocative tests: graded physical exertion (bicycle ergometry, treadmill test) and pharmacological tests (with atropine, propranolol, isoprenaline).
• Autonomic nervous system assessment: cardiointervalography.
• Exclusion of neurological factors: EEG, echoencephalography, rheoencephalography.
• Consultations with related specialists: endocrinologist, neurologist, ophthalmologist, and otolaryngologist (to identify chronic foci of infection).

Class and exam questions

What else to study on this topic

• Criteria and ECG signs of supraventricular (atrial and junctional) extrasystoles
• Re-entry mechanism and the development of paroxysmal tachycardia
• Wolff-Parkinson-White (WPW) syndrome as a cause of tachyarrhythmias
• Differential diagnosis of AV blocks (Mobitz I, Mobitz II, and complete block)
• Age-related ECG features and pediatric norms

Other topics in the "Additional Topics" section

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